1. Field of the Invention
The present invention relates to the field of technology pertaining to devices for imprinting a seal on the surface of a certification paper.
2. Description of the Prior Art
A printing device for impressing a seal on the surface of a certification paper is well known. The presence of the seal enhances the appearance of the certificate, such as one issued by a primary school or a university. Other certificate papers also require the impression of a seal to provide official certification of the paper, such as a patent or trademark certificate.
A conventional printing device for this purpose is manually operated, and is commonly known as a C-type steel seal printing device. Devices of this type are often used in schools or military installations, an example of which is shown in FIG. 1 wherein the basic structure includes three primary sections, including a C-shaped seat body 1, a feeding device 2 having a worm and worm gear, an upper steel mold 3 and a lower steel mold 4. Molds 3 and 4 are secured within respective upper and lower mold fixing blocks 10 and 11 on the opposite ends of the seat body 1. The article A to be impressed by the seal is placed onto the lower steel mold 4 and an operating handle 22 is pulled downwardly to rotate worm gear 21 which in turn causes worm 20 to move downwardly in a linear motion. This causes upper steel mold 3 to be pressed against the article so that the patterns carried by molds 3 and 4 are impressed in the article A.
Another known type of seal printing device is shown in FIG. 2. This type utilizes the principle of a lever. The manual operation of this device requires less energy than the operation of the previously described device, though the main structural characteristics of both devices are somewhat similar. The main difference being that the instant device does not include the worm and worm gear assembly.
However, known devices of the above types have been found to have certain disadvantages in structure and operation. For example, the upper and lower steel molds are securely fixed to their respective fixing blocks and are thus incapable of either rotary or linear adjustment. Also, the size of the seal impression on the article is confined to the limited space which is available due to the lack of adjustment. Further, manual operated printing devices are incapable of high production efficiency.